Rev - it's still about everyone's profit margins.
The dealer, the broker...everyone but the end customer. Rules of economics dictate that the more people involved in the transaction, the more people that each need to make a profit to substantiate their existence. Whomever this 'broker' contacts needs to maximize their own profit, regardless of who they are selling to. Pre-internet days, the use of a broker might have made sense as an alternative to scouring the car lots on a Sunday afternoon, typically many miles or towns apart.
Seems to me the simpler the transaction process, the better negotiating leverage we have as the consumer. The internet has shifted the whole car-buying process in favor of the buyer, but we still have to be diligent and keep ourselves informed and educated. The bottom line - the exact car we want in our garages or quonsett huts
, and more $$ in our pocket for nachos and drugs.